The present invention relates to a clock feeding system for a plurality of load units which belong to an electronic apparatus such as an electronic computer that carry out the control operation in synchronism with clock signals, and particularly to a clock feeding system which is capable of easily distributing the clock signals.
An electronic apparatus such as an electronic computer includes a plurality of load units each of which is operated by clock signals having discrete phases. Each clock signal that is fed to a load unit is synchronized with the other clock signals, because each load unit has to perform a preassigned function in a synchronized manner with the other load units.
According to a typical conventional clock feeding system for feeding clock signals to load units in an electronic apparatus, as disclosed by Japanese Patent Laid Open No. 23631/1984, clock signals of n phases are formed at one place in the system in a concentrated manner, and the clock signals of n phases are proliferated into signals of a number necessary for the plurality of load units. The load units can then be operated in synchronism with each other by the same clock signal.
According to another conventional clock feeding system, signals of an oscillation waveform generated by an oscillator and a start signal for synchronism are supplied to a plurality of load units in an electronic apparatus, and each load unit produces clock signals of n phases which the unit itself requires and which are in synchronism with clock signals of other load units, thereby reducing the amount of hardware for transmitting the clock signals over the first system.
According to the first mentioned conventional system, the technology which forms clock signals was of n phases at one place in a concentrated manner is undesirable in that a large number of transmission lines for transmitting the clock signals to the plurality of load units and buffer gates is needed. The number of such transmission lines is equal to the number of signals necessary, which is generally equal to the number to meet all n phases. Moreover, since the load units are used in many number, the phase deviation tends to increase among the load units, and there has to be provided many phase-adjusting portions to correct the phase deviation, thereby also requiring an increased number of adjusting steps.
According to the second mentioned conventional system, oscillation signals of the oscillator have to be supplied to the load units with associated start signals. When the oscillation frequency of the oscillator is high, coaxial cables and connectors of a wide band have to be used to propagate the high-frequency signals.
Current computer technology needs require an improved clocking signal feeding system that overcomes these problems and others, to provide a clock feeding system that has a minimal number of clock signal transmission lines, that avoids the need for an associated start signal and which has the capability to provide a plurality of corresponding phase shifted signals to a first predetermined clock signal.